Today there presently still remains a very significant risk on the part of medical professionals, of obtaining on the job infections of HIV, HBV (Hepatitis B), and other serious blood borne diseases as the result of contaminated needle stick injury. Many inventions and devices have been invented and proposed to help solve this problem; however to date, there is still no device on the market that sufficiently and cost effectively brings a solution to this problem. Needle stick injuries continue to occur at an alarming rate. This problem is also of significant concern in the area of veterinary medicine, which also needs to be addressed. It is possible for many animal diseases to be transmitted to humans via a contaminated needle-stick injury, some of which can be quite serious and even fatal.
Many needle devices have been made heretofore that still expose the sharp needle point during some time of the operation of the device, thus still exposing the medical worker to accidental needle-stick injury. Other safety syringes have been marketed that utilize a safety shield which must be manually pulled over the exposed sharp needle point after an injection. These devices are not effective in prevention of accidental needle-stick injuries, because they do not shield the sharp needle point during one of the most likely times for a contaminated needle stick injury; immediately after an injection. They are also difficult and cumbersome to use. Some in fact even seem to increase the chance of injury.
U.S. Pat. No. 4,813,940 dated Mar. 21, 1989 shows an injection device in which a pair of telescoping sleeve members receive a needle with an inner sleeve member covering the needle in an extended position. The inner sleeve member is manually rotated for movement from a locked position preventing retraction of the sleeve member, and an unlocked position permitting retraction of the sleeve member for injection or aspiration of a fluid from the needle. The outer sleeve member or housing is secured to an inner member in which the base of a needle is press fitted. While relative rotation between the inner and outer sleeve members is provided for unlocking of the sheath, only a pin in a track restricts or stops the manual rotation of the inner sleeve member or sheath. The manual rotation of the sheath, particularly if gripped at the projecting end of the sheath adjacent the sharp needle end is undesirable and may result in failure particularly if a large rotative force is applied.